Well drilling system



J 1968 J. R. IOANESYAN ETAL 3,

WELL DRILLING SYSTEM Filed July 12, 1965 S heet 1 INVENTOR5 Jam Fa hmm W2 4 Iwnesydfl 'Ba/erv 19mm rev/04 fwd/125 ATTORNEYS 1953 J. R. IOANESYAN E l'AL 3,

WELL DRILLING SYSTEM 4 Sheets-Sheee Filed July 12, 1965 INVENTORS' 710 nau/o/v [Danes en 1 9 WM [0 ATTORNEYS 1968 J. R. IOANESYAN ETAL 3,

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WELL DRILLING SYSTEM 4 Sheets-Sheet 4 Filed July 12, 1965 T INVENTORS Jwr' fi enw/frfi Lanes m fi /e /i sen 1 e via/7 parl sydn BY r ATTORNE 5 United States Patent 3,362,488 WELL DRILLING SYSTEM Jury Rolenovich Ioanesyan and Rolen Arseuievich loannesyan, both of Naberezhnaya Tarasa, Shevchenko 1/2, kv. 49, Moscow, U.S.S.R.

Filed July 12, 1965, Ser. No. 471,066 5 Claims. (Cl. 175-93) ABSTRACT OF THE DISCLOSURE A well drilling arrangement in which a turbodrill and bit are connected to drill pipes with the turbodrill being driven by a drilling fluid pumped down through the drilling pipes, and at least one ejector unit positioned in the path of flow of the drilling fluid prior to its passage into the turbine with the ejector unit being furnished with a portion of the fluid exhausted from the turbine for being repumped and circulated recurrently through the turbine.

The present invention generally comprises drill pipes, a turbodrill having a bit, means connecting the turbodrill with the drill pipes, with the turbodrill being driven by the drilling fluid pumped down through the drilling pipes, at least one ejector means positioned in the flow path of the drilling fluid prior to entry of the fluid into the turbine of the turbodrill, and means cooperable with the turbodrill and ejector means for directing a portion of the fluid exhausted from the turbine into the ejector means to be repumped by the ejector means and circulated recurrently through the turbine of the turbodrill.

At the present time there are turbodrills provided with 'multi-stage turbines which are capable of creating a high rotational speed at a relatively low shaft torque. The decrease in the speed and the increase in the shaft torque assist in a radical improvement of footage per bit, and thus of the total drilling efliciency.

The increase in the torque and the decrease in the rotational speed of the turbine shaft can only be attained, with the number of turbine stages unchanged, by a sharp increase in the supply of the drilling fluid to the turbodrill. Such method, however, in deep well boring is not feasible due to the impossibility of supplying the turbine with the required amount of drilling fluid caused by high losses of pressure in the drill pipes and the annular space.

The flow rate of drilling fluid through the turbine in the known types may be equal to or lower than the delivery rate of the mud pumps. The latter holds true for turbodrills equipped with reducing valves when a part of the drilling fluid passes to the bottom of a well, thus by-passing the turbine.

Accordingly, a principal object of the present invention is to provide a well drilling system comprising a turbodrill which, at a relatively low consumption of the drilling fluid supplied by the mud pu-mps, will produce a high shaft torque of the drill at a limited rotational speed.

According to the present invention, there is provided a turbodrill in which the circulation rate of fiuid flowing through its turbine is higher than that delivered by the mud pumps.

This object is attained by incorporating in the well drilling assembly at least one ejector located in the path of the drilling fluid stream before it passes into the drill turbine, with the ejector producing a supplementary closed circuit by re-pumping a part of the fluid exhausted from the turbine.

One embodiment of the present invention includes a turbodrill having a hollow shaft and ejectors which are disposed above the drill turbine with case openings being provided in the lower part of the shaft for discharging a part of the fluid exhausted from the turbine and passing it to the bit and admitting the remaining part of the fluid Patented Jan. 9, 1968 re-pumped by the ejectors to the turbine and the hollow shaft being connected with the suction pipe of the ejectors. A seal is provided between the suction pipe and the turbodrill shaft and such seal is preferably defined by an interstice between the shaft and suction pipe.

Further, according to the present invention, a hollow shaft turbodrill is provided with ejectors disposed underneath the turbine, with the suction pipe of the ejectors being rigidly connected with the hollow shaft and openings in the upper part of the casing provide a passage for the fluid discharged from the turbine to the annular space. The fluid is partially re-pumped from the annular-space by the ejectors and passed to the turbine through openings in the bit thereby providing for the rotation of the drill casing together with the bit connected thereto.

When a solid shaft is employed, the ejectors are disposed above the drill turbine and the lower part of the solid shaft is provided with a channel for passing a part of the fluid exhausted from the turbine to the bit while the upper part of the casing has openings for admitting a part of the fluid repumped by the ejectors from the annular space.

According to a further aspect of the invention, the ejectors may be accommodated in a sub above the turbodrill and inlet openings for the fluid re-pumped from the annular space by the ejectors are provided in the sub.

Additional objects and advantages of the invention will become more readily apparent to persons skilled in the art from the following detailed description and annexed drawings and in which drawings:

FIGURE 1 is a view partly in elevation and partly in cross-section of the lower end of an embodiment of the invention in which the ejectors are disposed above the turbine of a hollow shaft drill,

FIGURE 1a is a view similar to FIGURE 1 of the upper end,

FIGURE 2 is a view partly in elevation and partly in cross-section of an embodiment in which the ejectors are disposed under the turbine of a hollow shaft drill,

FIGURE 3 is a view partly in elevation and partly in cross-section of the upper end of an embodiment wherein the ejectors are accommodated in the sub of a solid shaft turbodrill and its connection to the lower end,

FIGURE 3a is a fragmentary view partly in elevation and partly in cross-section of the lower end shown in FIGURE 3.

FIG. 4 is a diagram of the turbine curves for various values of the rotational speed and turbine blading of a standard shape,

FIG. 4a is a view illustrating a standard shape blading of the turbine,

FIG. 5 is a diagram of the turbine curves of the turbodrill for various rotational speeds and turbine blading shaped so that the flow of the fluid is obtained without a surging shock and with the rotor immovable,

FIG. 5a is a view illustrating the turbine blading shaped so that the flow of the fluid is obtained without a surging shock with the rotor immovable,

FIG. 6 is a diagram of the turbine curves for various rotational speeds and a turbine embodying blading of a propeller shape, and

FIG. 6a is a view of a propeller-shape blading.

Referring to FIGURES 1 and 1a, a turbodrill 2 is connected to a drill string 1 and includes a hollow shaft 3 carrying a multi-stage turbine 4 adapted to be driven by a drilling fluid pumped down through the drill string 1.

A plurality of ejectors 6 operated in parallel are provided in the upper part of a casing 5 of the turbodrill 2 and are located in the path of the fluid flow. Nozzles 7 of the ejectors 6 are secured to the peripheral part of a disk 8 rigidly connected with the casing 5. Mixing chambers 10 of the ejectors 6 are fixed in the casing 5 coaxially with the nozzles 7 thus forming therewith an annular clearance or space 9. The chambers 10 are positioned above the turbine 4 blading of the multi-stage turbine 4.

The hollow shaft 3 is connected with a suction pipe 11 for the ejectors 6 through a seal 12 preferably and interstice. The connection of the shaft 3 and the suction pipe 11 may be effected through a conventional type seal. The nozzles 7 of the ejectors 6 should be of a hard alloy or ceramic material.

The drilling fluid stream passes at a high rate from the nozzle 7 to the mixing chambers 10, and thence to the turbine 4. The turbine-exhausted fluid passes partially to the bit through an opening 13 in the shaft 3, while a part of the exhausted fluid is re-pumped from the annular space 9 by the ejectors 6 and re-supplied to the turbine 4. Thus, the system of supplying the drilling fluid to the turbine produces a supplementary closed circuit through the turbine 4, hollow shaft 3 and the mixing chambers 10 of the ejectors 6.

The embodiment of the invention illustrated in FIG- URE 2 provides for a supplementary closed circuit through the turbine 4' annular space and mixing chainbers 10 of the ejectors 6 in which cleaning of the bottom is improved. It will be seen that a casing 14 of the turbodrill 2 may rotate relative to the hollow shaft 3' by means of bearings 15. Jet pumps or ejectors 6 are rigidly connected with the shaft 3' at their suction pipe 11 and are disposed beneath the turbine 4. As was the case in FIGURE 1, the ejectors 6 operate in parallel.

Openings 16 in the upper part of the casing 14 serve to discharge the turbine-exhausted fluid into the annular space between the turbodrill and the wall of the bore, and a part of the fluid is re-pumped by the ejectors 6 into the turbine 4 through an opening 17 in a bit 18.

It is obvious to those skilled in the art that in this embodiment of the invention, the casing 14 may be immovable while the shaft 3' with the bit fixed thereto is rotatable. The opening 17 may be disposed in the lower part of the casing 14 rather than in the bit.

The embodiments of the invention described above are preferable for use with large diameter turbodrills but it is relatively difficult to embody a hollow shaft in a small diameter turbodrill.

To accomplish this end, the turbodrill as shown in FIGS. 3 and 3a is provided with a solid shaft 19. The ejector 6" is accommodated above the turbodrill 2" in a sub 20, which may be disposed either directly above the turbodrill 2" or at some distance therefrom, e.g. one pipe distance. The ejector 6 may also be accommodated in the casing 14" of the turbodrill.

A channel 21 in the lower part of the shaft 19 communicates with the interior of the turbine 4 for passing the fluid discharged from the turbine 4" to the bit. Openings 22 in the sub admit a part of the turbine-discharged fluid, with such part being re-pumped by ejectors 6" from the annular space. Cleaning filters 23 should be included in turbodriils having a closed circulation system produced by re-pumping the fluid from the annular space.

Depending upon the drilling conditions and the type of bit used, the amount of the fluid re-purnped by the ejectors may be varied so that such amount is maintained constant irrespective of the bit rotational speed. It may also happen that the amount of fluid re-pumped with the ejectors will increase while the bit rotational speed is reduced and this is particularly effective in the case of roller or drag bits. It is desirable and effective sometimes for the amount of the re-pumped fluid to be increased with the increase in the rotational speed, and such is the case with diamond bits.

A constant or variable amount of the re-pumped fluid is attained by using turbine blading of a corresponding snape.

If :a constant amount of the fluid re-pumped is desirable, the blading of the turbine is given a standard shape as shown in FIG. 4a. It is known that with the blading of a standard shape, the stator inlet angle (t and the rotor inlet angle [3 equal whereas the stator outlet angle in equals the rotor outlet angle fig. Thus shape of the blading will ensure a flow without a surging shock equaling one half the idle speed of rotation. The turbine curves of this embodiment are shown in FIG. 4.

If a larger amount of fluid at a low rotational speed, or a smaller amount of fluid at a high rotational speed is needed, the blading of the turbine is given such a shape that a flow without a surging shock is attained with the rotor immovable. B-lading of such a shape is shown in FIG. 5a. It is obvious that with this type of blading the stator inlet a and outlet 1x angles are equal, while the rotor inlet 5 and outlet {3 angles are likewise equal. The turbine curves for this turbodrill are shown in FIG. 5.

When a larger amount of fluid is to be re-pumped at a higher rotational speed, the blading should be given a propeller shape (FIG. 6a) and turbine curves for this embodiment are illustrated in propeller shape, FIG. 6.

In FIGS. 4-6, the full line M denotes the drill shaft torque, the line H the pressure in the drill turbine, the line Q the amount of fluid delivered by the mud pumps and the dotted line Q the amount of fluid re-pumped by the ejectors.

By regulating the amount of fluid re-pumped, the bit rotational speed for effective drilling may be varied at will. If desired, or needed, a rotational speed standard for rotary drilling may be attained in operation.

The invention is not to be confined to any strict conformity to the showings in the drawings but changes or modifications may be made therein so long as such changes or modifications mark no material departure from the spirit and scope of the appended claimsi We claim:

1. A system for drilling wells including: drill pipes, a turbodrill having a bit; said turbodrill being connected with said drill pipes and driven by drilling fluid pumped down through said drilling pipes; at least one ejector located in the path of the drilling fluid flow before entry of the fluid into the turbine of said turbodrill; and means cooperable with the turbodrill and ejector for directing a portion of the fluid exhausted from said turbine to the ejector to be repumped by said ejector and circulated recurrently through the turbine of said turbodrill.

2. A system for drilling wells including: drill pipes; a hollow shaft turbodrill having a bit; said turbodrill being connected with said drill pipes and driven by the drilling fluid pumped down through said drill pipes; ejectors accommodated above the turbine of said turbo drill; said hollow shaft of the drill having openings in its lower part for passing a portion of the fluid exhausted from the turbine to the bit, and the remaining portion of the fluid through the hollow-shaft to said ejectors for being repumped by the ejectors into the turbine; a suction pipe for said ejectors; and seal means connected by said suction pipe with the hollow shaft.

3. A system for drilling wells including drill pipes; a hollow shaft turbodrill having a bit provided with an opening; said turbodrill "being connected with said drill pipes and driven by the drilling fluid pump down through said drill pipes; ejectors accommodated underneath the turbine of said turbodrill; a suction pipe for said ejectors connected to the bit opening; a casing for said turbodrill provided with openings in its upper part to discharge the fluid exhausted from said turbine into the annular space between said casing and the well bore; and a portion of the exhausted fluid entering said ejectors through said bit opening and being repumped by said ejectors into said turbine.

4. A system for drilling wells including drill pipes; a solid shaft turbodrill provided with a 'bit; said turbodrill being connected with said drill pipes and driven by the drilling fluid which is pumped down said drilling pipes; ejectors accommodated above the turbine of said turbodrill; said solid shaft of the turbodrill being provided with a channel in its lower part for passing the fluid exhausted from said turbine to said bit; said turbodrill being provided with openings in its upper part for admitting a portion of the exhausted fluid which is repumped from the annular space between the turbodrill and the Well bore by said ejectors and then circulated through said turbine of said turbodrill.

5. The drilling system as claimed in claim 4, wherein said ejectors are accommodated in a sub located above said turbodrill, and said openings for admitting a portion of the fluid exhausted from the turbine and repumped by said ejectors from the annular space being :located in said sub.

6 References Cited UNITED STATES PATENTS CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner. 

